R75/6 SMOKING

[JACK KOPP]

NOT REALLY A PROBLEM AS MUCH AS A PAIN IN THE NECK THAT LOOKS BAD. WHEN I PARK MY /6 ON THE SIDE STAND FOR ANY LENGTH OF TIME I GET LOTS OF WHITE SMOKE AT START UP, LIKE THE THING IS RUNNING VERY RICH. WHEN I PARK ON THE CENTER STAND I DON'T GET THIS PROBLEM. ANY THOUGHTS? IT IS AN UNMODIFIED ENGINE WITH BING CARBS AND OTHERWISE RUNS LIKE IT WAS NEW.

[Rainer]

Hi Jack,
this problem is well known. On the side stand oil is passing the piston rings and
will be burned after starting. You should use the center stand for longer breaks.
regards
Rainer

[Tom Hagan]

A trick that will help a bit is to lean the bike to the right for a few seconds after shutting the engine off and before putting it on its sidestand. This allows oil in the cylinder and behind the piston to drain back into the crankcase.

Using the center stand instead of the sidestand whenever possible is the best advice.

Tom

[Mark Huggett]

This is not a problem, but rather a characteristic of boxer motors including VW, Porsche, Subaru, Alfa Sud, Citroen etc. It is also a BMW K characteristic, or was. Modern day piston rings are constructed to rotate in 4 stroke engines. If it so happens that when one kills the motor, that the piston rings happen to stop rotating with the gap in the lower position, then oil will seap through that gap and collect in the combustion chamber. Starting the bike then becomes an embarrassing procedure when people are standing around (with their rice bowls). Kolben Schmidt solved this problem with the BMW K series by pinning the piston rings (like with 2-stroke pistons) so that they no longer rotate. That way, the piston ring gap can no longer be at the bottom, and you no longer have to smoke out onlookers when starting your motor off the side stand.

Regards,

Mark
Mark Huggett GmbH